Atoms A and B form an ideal solution at $T=1000K.$ If the free energy of pure $A$ is $G_A=50k\frac{J}{m}ol$ and

that of pure B is $G_B=70k\frac{J}{m}ol.$

$($a$)$ Compute and draw the free energy of $1$ mole of $\frac{A}{B}$ ideal solution with arbitrary composition.

Hand drawing is okay, but do label the magnitudes.

$($b$)$ What will be the free energy drop when mixing $0\mathrm{.}4$ mole of A and $3$ moles of B into an ideal

solution at this given temperature?